The present invention relates to adapter assemblies.
During certain medical procedures, for example a continuous epidural or caudal spinal anesthesia procedure, it is necessary to connect a syringe to an end of a catheter. In a continuous epidural anesthesia procedure, a needle is positioned in a patient's body with an opening at one end of the needle positioned in the epidural space of the patient and with the other end of the needle extending outside the patient's body. A catheter of relatively small diameter is threaded through the needle and the needle opening until a distal end of the catheter is located in the epidural space, while a proximal end of the catheter extends outside the patient's body. The needle is removed from the patient's body and from the catheter to prevent obstruction if the operation takes place with the patient lying on his back and to prevent the needle from cutting the catheter during the operation. After removal of the needle, an anesthetic solution is injected through the catheter into the epidural space by a syringe which is connected to the proximal end of the catheter.
Accordingly, a connector or adapter must be provided for connecting the syringe to the proximal end of the catheter. The adapter should be positionable on the catheter after removal of the needle from the catheter, since the adapter would otherwise prevent removal of the needle from the catheter. It is also desirable that the adapter should permit easy placement on the catheter to expedite the procedure.
After the syringe has been connected to the adapter, the anesthetic solution is injected through the catheter into the epidural space. A relatively large amount of the solution is initially required for epidural anesthesia, with additional amounts of the solution being periodically injected during surgery. it is preferred that the syringe be removed from the adapter between injections, since if the syringe remains connected to the adapter and if the syringe inadvertently falls from the bed or other structure on which it is placed, the weight of the connected syringe may pull the catheter from the patient's body, necessitating repositioning of the catheter into the epidural space during surgery if further anesthesia is required.